Safety stop or brake for elevators



Nu.6oa,297. Patented Aug. 2,1898.

w. G..McG-|-:E. SAFETY sToP on BRAKE Fon ELEvATgns.

(Application led Sept. 16, 1897.)

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A TTOBNEYS- UNITED vSTATES PATENT Finca,

VILLIAM GLENN MCGEE, OF WILMINGTON, DELAVARE.

SAFETY STOP OR BRAKE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 608,297, dated August2, 189s.

Application le September 16, 1897. Serial No. 651,914. (No model.)

This invention relates to that class of safety stops or brakes forelevators which are designed to operate in the event of the breakage ofthe suspending ropes or cables; and it has for its object to provide asimple and improved pneumatic safety elevator-stop of this characterwhich will possess advantages in point of simplicity, positive action,safety, effectiveness, and general efficiency.

In the drawings, Figure l is an elevation, partlyin section, showingmyimproved safety mechanism in connection with the elevator. Fig. 2 is adetail vertical sectional view taken through the top of one of thecylinders.

Referring to the drawings, A designates anelevator-car which may besuspended by ropes or cables B and operate in any suitable or desiredmanner.

At the sides of the elevator-shaft and coextensive with the length oftravel of the elevator-car are arranged verticall cylinders C,preferably one at each side, in each of which is arranged an air-tightpiston D. From the top of the piston extends a rope or cable E up overwheels or pulleys F, arranged at the top of the elevator-shaft, anddownwardly to the top of the elevator-car. From the bottom of the pistonextends a similar rope orv cable G downwardly under similar'wheels orpulleys II, arranged at the bottom of the elevatorshaft, and up to thebottom of the car.

The top of the cylinderv O is closed by a cap c, having an opening c',through which the cable E passes, this opening being large enough inrelation to the diameter of the cable to'permit the escape ofasufficient quantity of air from the cylinder during the normal descentof the elevator-car.

The bottom end c2 of the cylinders O is opened, and a door Ifmay beprovided in the side wall of the cylinder at the bottom or at any othersuitable point, which will permit inspection of the piston when desired.

The end of the upper ropes or cables E which is connected to the top ofthe piston is gradually tapered or enlarged to its point of connectionwith the piston, as shown at e. This tapering or enlarged portion ispreferably exteriorly smooth and corresponds in its greatest enlargementto the diameter of the opening c', so that it will operate toeffectively close the latter.

The operation and advantages of my invention will be readily understood.As the elevator ascends the lower ropes or cables G operate to draw thepistons in the cylinders, there being no compressed-air resistance inthis operation by reason of the fact that the bottom of the cylinder isopen. As the elevator-car descends the upper ropes or cables E operateto draw the piston up in the cylinder against the air resistance andthe-compressed air will normally'escape through the top opening c of thecylinder in sufficient quantity so that the ordinary speed of theelevator-car in its descent will not be retarded; but should thesuspending rope or cable B break or the elevator-car for any reason bereleased from its supporting mechanism the action of the piston againstthe compressed air in the cylinder and the escape of the air through theopening c' will simply result in a slight increase in the speed ofthecar in its descent by gravity until theend enlargement e registerswiththe opening c', when the enlargement operates to gradually close theopening and shutoff the escape of the compressed air and finally andentirely closes the opening and forms a complete cushion,which willsustain the elevator-car against further descent.

By reason of the improved construction and arrangement comprised in myinvention as above described lthe automatic speed of the elevator-car isgradually accomplished without shock or jar.

I preferably employ two cylinders, with their connected stop mechanism,one at'each side the elevator-shaft, sothat in the eevent of one of thecylinder mechanisms becoming inoperative the other would stilleffectively operate to sustain and stop the descent of the elevator-car.

It will also be understood that my improved IOO automatic safetyelevator-stop serves at all times to prevent excess speed of the ear inits descent, the desired speed being readily adjusted by the relativesize of the air-escape opening c' with relation to the diameter of theupper ropes or cables E.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. In an improved pneumatic safety eleVator-stop mechanism,comprising acompressedair cylinder having an opening in its head and carrying apiston, the combination therewith of a rope or cable having a taperedend and extending from said piston through the opening and to theelevator-ear, the size of the escape-opening with relation to thedialneter of the end of said cable operating to regulate the escape ofthe compressed air in the cylinder with respect to the speed of the car,substantially as and for the purpose set forth.

i. The herein-described improved pneumatie safety elevator-stopmechanism, comprising the vertieal compressed-air Cylinders arranged atthe sides of the elevator-shaft and having an open bottom and a closedtop in which is formed an air-escape opening, pistons operating saidcylinders, the guide wheels or pulleys at the top of the elevator shaft,the guide wheels or pulleys at the bottom of the elevator-shaft, weightsor cables extending from the pistons around the bottom pulleys and tothe elevator-ear, and the upper ropes or cables extending from thepistons through the top ai r-escape openings over the top pulleys and tothe top of the elevator-ear, said upper ropes or cables being in theirmain portion of less diameter than said escapeopenings and having atapering enlargement adapted to gradually close the latter,substantially as and for the purpose set forth.

In testimony that I claim the foregoing as my invention I have signed myname, in presence of two witnesses, this 13th day of September, 1897.

VILLIAM GLENN MCGEIC. Witnesses:

(f1. Wn. K. lnanronn, Cuanmcs ll'. Seo'r'r.

